Prevent stack overflow problem when formula in a cell contains a named range without a worksheet reference... this doesn't fix the formula, but does avoid the exception and allows the workbook to be written with the problematic cell as a blank

git-svn-id: https://phpexcel.svn.codeplex.com/svn/trunk@86488 2327b42d-5241-43d6-9e2a-de5ac946f064

Classes/PHPExcel/Writer/Excel5/Parser.php

@@ -1055,6 +1055,7 @@ class PHPExcel_Writer_Excel5_Parser
 
 		while ($i < $formula_length) {
 			$token .= $this->_formula{$i};
+
 			if ($i < ($formula_length - 1)) {
 				$this->_lookahead = $this->_formula{$i+1};
 			} else {
@@ -1183,6 +1184,11 @@ class PHPExcel_Writer_Excel5_Parser
 				{
 					return $token;
 				}
+				//	It's an argument of some description (e.g. a named range),
+				//		precise nature yet to be determined
+				elseif(substr($token,-1) == ')') {
+					return $token;
+				}
 				return '';
 		}
 	}